'Dory' is set to be released this summer and features the return of 'Finding Nemo' stars Ellen DeGeneres and Albert Brooks. Pixar's previous film, last summer's 'Inside Out,' was a critical and box office smash.

Pixar has released a new trailer for its upcoming animated sequel, “Finding Dory.”

Fans of Pixar’s 2003 movie “Finding Nemo” know that fish Dory (voiced by Ellen DeGeneres) has trouble remembering things. In the new movie, though, something has come back to her. She remembers, “My family – they’re out there somewhere.”

The trailer also shows that Dory has a habit of “sleep-swimming,” which means neighbors Marlon (Albert Brooks) and Nemo (Hayden Rolence) have to keep an eye on her.

“Finding Nemo” was a relatively early release for the studio. Before 2003, Pixar had released “Toy Story” and “Toy Story 2,” both box office hits and hits with reviewers, as well as “A Bug’s Life,” which had a modest box office gross and a mixed critical reception. “Monsters, Inc.” had also come out and done quite well at the box office and with critics.

“Nemo,” however, blew the others out of the water (sorry). It became the highest-grossing Pixar film released so far and was the highest-grossing computer animated movie of all time until “Shrek 2” came along the next summer.

Pixar rode this wave of success (all right, I’ll stop) over the next several years. “The Incredibles,” “WALL-E,” and “Up” were all rapturously received (“Up” became the first animated movie to be nominated for the Best Picture Oscar since 1991’s “Beauty and the Beast,” though it was also released in a year in which the Academy increased the amount of films that could receive that honor). “Ratatouille” was a more modest performer, but by no means a failure and was a big hit with critics. “Cars” got a more mixed critical reception, but did well at the box office.

Then another smash came with “Toy Story 3,” which was released in 2010 and is still the highest-grossing movie released by Pixar. “Toy” also earned a Best Picture nod.

Pixar entered a slight slump after “Toy,” however – a string of performers that might have been fine at other animation studios but was a low point for the great results Hollywood is used to from Pixar. “Cars 2” was a critical misfire and is one of Pixar’s lowest box office performers, the closest Pixar has to a failure (the movie still did well at the box office, just not as well as other movies from the studio). 2012’s “Brave” got a mixed critical reception. 2013’s “Monsters University” did better at the box office, but was not a hit with critics, either.

As “Cars 2” and “University” were released and Pixar announced “The Incredibles 2” and “Cars 3,” it was a significant shift for the studio. Before “Cars 2,” the “Toy Story” films were the only story Pixar continued across multiple films. Since “Monsters University” and “Cars 2” were not critical hits, animated movie fans may have worried that Pixar’s creative standard was slipping.

The studio’s on top of the world following this summer’s original story “Inside Out,” however. “Inside” scored with critics and is in the top five of the highest-grossing movies this year so far. Pixar president Ed Catmull previously stated a plan to do “an original movie a year” and the studio will actually release two this year, with “The Good Dinosaur” due later this month. “Dory” is the only movie set for 2016 right now, then 2017 will find the studio releasing “Cars 3” and a film called “Coco."

“Inside” was certainly a good sign for fans fearing Pixar’s movies were in a creative slump and that the studio was focusing more on sequels. If the studio’s next original story, “Dinosaur,” scores as well, the studio will have shaken off a few lackluster stories.